Subject: [PATCH 2/2] selinux: use netlink_receive hook

From: Jeff Vander Stoep <[email-masked]>
Date: Wed, 21 Aug 2019 15:46:16 +0200

Add the nlmsg_readpriv permission to netlink_route socket class.
Currently this is only used to restrict MAC address access.

Signed-off-by: Jeff Vander Stoep <[email-masked]>
---
 security/selinux/hooks.c            | 6 ++++++
 security/selinux/include/classmap.h | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 74dd46de01b6..2ab89a73f663 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -5825,6 +5825,11 @@ static unsigned int selinux_ipv6_postroute(void *priv,
 
 #endif	/* CONFIG_NETFILTER */
 
+static int selinux_netlink_receive(struct sock *sk, struct sk_buff *skb)
+{
+	return sock_has_perm(current, sk, NETLINK_ROUTE_SOCKET__NLMSG_READPRIV);
+}
+
 static int selinux_netlink_send(struct sock *sk, struct sk_buff *skb)
 {
 	return selinux_nlmsg_perm(sk, skb);
@@ -6765,6 +6770,7 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(syslog, selinux_syslog),
 	LSM_HOOK_INIT(vm_enough_memory, selinux_vm_enough_memory),
 
+	LSM_HOOK_INIT(netlink_receive, selinux_netlink_receive),
 	LSM_HOOK_INIT(netlink_send, selinux_netlink_send),
 
 	LSM_HOOK_INIT(bprm_set_creds, selinux_bprm_set_creds),
diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h
index 201f7e588a29..3726c61a3dd1 100644
--- a/security/selinux/include/classmap.h
+++ b/security/selinux/include/classmap.h
@@ -115,7 +115,7 @@ struct security_class_mapping secclass_map[] = {
 	  { COMMON_IPC_PERMS, NULL } },
 	{ "netlink_route_socket",
 	  { COMMON_SOCK_PERMS,
-	    "nlmsg_read", "nlmsg_write", NULL } },
+	    "nlmsg_read", "nlmsg_write", "nlmsg_readpriv", NULL } },
 	{ "netlink_tcpdiag_socket",
 	  { COMMON_SOCK_PERMS,
 	    "nlmsg_read", "nlmsg_write", NULL } },
-- 
2.23.0.rc1.153.gdeed80330f-goog